1. Technical Field
The present invention relates to a blast processing device and a blast processing method.
2. Related Art
Blast processing is known conventionally as a surface processing technique in which hard particles are blasted by compressed air so as to impinge on a surface of a workpiece such as a machined component or a painted component. With blast processing, rust and dirt on the surface of the workpiece can be removed. Blast processing is therefore used mainly as priming processing performed during painting or the like, and surface processing such as paint stripping and shot peening.
Blast processing is performed by blasting a blasting material toward a workpiece together with compressed air from a blast processing nozzle. A conventional blast processing nozzle is configured by providing a conical deflecting member that widens toward the workpiece side on one end of a cylindrical flow passage pipe that is open at both ends. The blasting material is blasted along a surface of the conical deflecting member in a 360 degree direction and a diagonal direction (see Japanese Unexamined Patent Application Publication (JP-A) Nos. 2010-64194 and H7-52046, for example).
A shot peening device having a flattened or angular tube-shaped cross-section, in which a tubular diffusing member that widens toward a workpiece is provided on a tip end of a cylindrical nozzle and a triangular flat plate-shaped diffusing body is provided inside an open end of the tubular diffusing member, has also been proposed (see JP-A No. 2002-120153, for example). With this device, a width of a peening range formed from a combination of rectangular regions can be adjusted. Further, an angle of a shot direction on an identical plane to an axial direction of the nozzle, or in other words a rotation angle of the shot direction about a single axis, can be adjusted.
Furthermore, a blast processing nozzle in which a blasting material blasting region is formed as an anisotropic region in accordance with a shape of a workpiece by partially blocking a circular blasting port so that a surface of a columnar component having an H-shaped, I-shaped, L-shaped, T-shaped, or other cross-section can be blasted efficiently has been devised (see JP-A No. 2013-129021, for example).
When a plurality of surfaces are blasted simultaneously, it is important to blast the blasting material onto the workpiece more efficiently and under more favorable conditions. For example, components of an aircraft include a stringer having an I-shaped cross-section, and the I-shaped stringer must be primed prior to painting. The I-shaped stringer has three orthogonal surfaces on either side. It is therefore important to blast the three orthogonal surfaces under conditions that are more favorable for priming.